Light-enabled metal-free pinacol coupling by hydrazine
作者:Zihang Qiu、Hanh D. M. Pham、Jianbin Li、Chen-Chen Li、Durbis J. Castillo-Pazos、Rustam Z. Khaliullin、Chao-Jun Li
DOI:10.1039/c9sc03737c
日期:——
Efficientcarbon–carbonbondformation is of great importance in modern organic synthetic chemistry. The pinacol coupling discovered over a century ago is still one of the most efficient coupling reactions to build the C–C bond in one step. However, traditional pinacol coupling often requires over-stoichiometric amounts of active metals as reductants, causing long-lasting metal waste issues and sustainability
高效的碳-碳键形成在现代有机合成化学中非常重要。一个多世纪前发现的频哪醇偶联仍然是一步构建 C-C 键的最有效偶联反应之一。然而,传统频哪醇偶联通常需要过量化学计量的活性金属作为还原剂,从而导致长期存在的金属废料问题和可持续性问题。一个巨大的科学挑战是设计一种无金属的频哪醇偶联反应方法。在这里,我们描述了一种光驱动频哪醇耦合协议,不使用任何金属,但使用 N 2 H 4,用作清洁的非金属氢原子转移 (HAT) 还原剂。在这种转化中,只有无痕无毒的N 2和H 2气体作为副产物产生,具有相对广泛的芳香酮范围和良好的官能团耐受性。对该机制的实验和计算研究表明,这种新颖的频哪醇偶联反应是通过光激发酮和 N 2 H 4之间的 HAT 过程进行的,而不是金属还原剂的常见单电子转移 (SET) 过程。
Thermal reaction of 2-methyl-2-butene in the presence of azomethane: enthalpy of formation of the radicals (CH3)2ĊCH(CH3)2 and tert-Ċ4H9
作者:Zoltán Király、Tamás Körtve´lyesi、László Seres
DOI:10.1039/a907433c
日期:——
The reaction of ĊH3 and 2-methyl-2-butene (2MB2) was investigated in the temperature range 540610 K. Azomethane was used as the source of ĊH3. The addition of ĊH3 to 2MB2 was concluded to be an equilibrium process: ĊH3+(CH3)2C2CHCH3(CH3)2ĊCH(CH3)2. The equilibrium constant of this reaction was determined from the rates of formation of the combination products (E)- and (Z)-CH3CH2C(CH3)2CHCH3 and (E)-
Scandium-Promoted Direct Conversion of Dinitrogen into Hydrazine Derivatives via N–C Bond Formation
作者:Ze-Jie Lv、Zhe Huang、Wen-Xiong Zhang、Zhenfeng Xi
DOI:10.1021/jacs.9b04293
日期:2019.6.5
scandium-mediated synthetic cycle affording hydrazine derivatives (RMeN-NMeR') directly from N2 and carbon-based electrophiles. The cycle includes three main steps: (i) reduction of a halogen-bridged discandium complex under N2 leading to a (N2)3--bridged discandium complex via a (N2)2- intermediate; (ii) treatment of the (N2)3- complex with methyl triflate (MeOTf), affording a (N2Me2)2--bridged discandium